Adiabatic sound absorber with high thermostability

Abstract

Provided is a flexible adiabatic sound absorber with high thermal insulation performance and acoustic performance, particularly an adiabatic sound absorbing material that is suitable for a new severe requirement specification regarding aircrafts. The adiabatic sound absorber comprises mixing uniformly 20 to 80% of a high-thermostable inorganic fiber whose high-temperature strength is maintained at 1000° C. or more, 10 to 60% of a flame-retarded organic fiber whose thermal melting or decomposition temperature is 350° C. or more and 10 to 25% of an organic fiber having a low melting point and treating the obtained woolly felt with heating to transform the whole into the mat-form material of 8 to 50 mm in thickness.

Description

TECHNICAL FIELD[0001]The present invention relates to a flexible and thermostable adiabatic sound absorber with high thermal insulation performance and acoustic performance, more particularly it relates to an adiabatic sound absorbing material suitable for a new severe requirement specification for aircrafts.BACKGROUND ART[0002]In Japan, a sound absorber molded into plates was used for railroad cars, in which a glass wool and rock fiber was impregnated with a small amount of organic synthetic resin, as disclosed in JP-S63-19622-B4. When the impregnated resin is combustible, this sound absorber generates a toxic gas during burning. The car weight is also apt to increase because the absorber is not lightweight. In JP-H06-47715-U, by which this defect was improved, a lap of a sintered flameproof acrylic fiber was punched with needles, on which a face sheet comprising a needle felt or woven cloth made of a sintered flameproof acrylic fiber was attached. The sound absorber thus obtained ...

AI Technical Summary

Benefits of technology

[0032]An adiabatic sound absorber according to the present is almost perfectly nonflammable and has high thermal insulation performance and sound absorbency because a primary component of the mat-form material is a high-thermostable inorganic fiber and an organic component thereof is flame-retarded. The adiabatic sound absorber of the present invention may therefore be used for an acoustic material for various automobile and railroad cars, and furthermore is suitable for a new severe requirement specification for aircrafts.

[0033]The adiabatic sound absorber of the present invention has higher safety than before on the occasion of the arrangement in an automobile and railroad cars, an aircraft and the like owing to the adaptation to the severe requirement specification for aircrafts, which can be expected to trade voluminously in goods for an aircraft. The adiabatic sound absorber may be also applied sufficiently to rapid-transit railroad cars in various nations conforming to the British Standard for cars.

[0034]It is possible to transform the adiabatic sound absorber of the present invention on the occasion of an arrangement thereof by adding the relatively flexible flame-retarded organic fiber to the relatively rigid thermostable inorganic fiber. The adiabatic sound absorber of the present invention may be processed to an entirely uniform mat-form material with heat treatment only, whose component fibers hardly snap off on the occasion of the after processing, by mixing uniformly a small amount of the low-melting organic fiber or adding a resin binder. The adiabatic sound absorber of the present invention is a soft and handy mat-form material, which makes hardly a working environment worse owing to few falling of fibers when cutting off or transforming it in case of the execution.

Problems solved by technology

When the impregnated resin is combustible, this sound absorber generates a toxic gas during burning.

The car weight is also apt to increase because the absorber is not lightweight.

This sound absorber was insufficient for sound absorbency though it is proof against high temperature, when it was mounted in the vicinity of an exhaust muffler that became considerably a high temperature in an engine room.

On this sound absorber, thermal resistance of the face materials was insufficient to be used for an engine room where high thermal resistance was required because both a melting point of the staple fiber and the synthetic fabrics was 300° C. or less.